1. Field of the Invention
The present invention relates to an inner pressure filling apparatus for filling pressurized air into an interior portion of a tire-rim assembly with a pneumatic tire being fitted on a rim. More particularly it relates to an inner pressure filling apparatus which is capable of uniformly bringing a bead portion of a pneumatic tire into close contact with a rim during filling of pressurized air into the interior portion of the tire-rim assembly.
2. Description of the Related Art
An inner pressure filling apparatus for a tire-rim assembly in which a pneumatic tire is merely fitted on a wheel rim has been disclosed mainly in Japanese Patent Application Publication No. 53-23563 and Japanese Patent Application Laid-Open No. 5-58123 filed by the assignee of the present application.
These disclosed prior art apparatus each have drawbacks as will be described hereinafter.
(1) Japanese Patent Application Publication No. 53-23563 PA0 (2) Japanese Patent Application Laid-Open No. 5-58123
This prior art apparatus is constructed in that a tire-rim assembly is mounted on a table which is movable upward and downward, and pressurized air is filled in an internal space of a tire from an upper side thereof through an air-tight ring or the like, which corresponds to an outer cylinder of the present invention. In this arrangement, the tire-rim assembly is disposed between upper and lower sections of the apparatus. For this reason, an entire construction of the apparatus becomes complicated and the apparatus is expensive to manufacture.
Further, since a peripheral edge of the above-described air-tight ring is not inclined with respect to a vertical direction axis, it is difficult for a bead seat of a wheel rim and a bead portion of a tire to be uniformly brought into close contact with each other. Thus, in most cases, the inherent performance of the tire could not be obtained.
The prior art disclosed therein is constructed in that a mounting mechanism of a taper cone which corresponds to a center guide of the present invention to center a wheel rim on a mounting table is complicated, and the wheel rim is centered by being pressed against the mounting table by a cylinder, while the taper cone is engaged with a hub hole on a disk of the wheel rim from an upper side of the apparatus.
For this reason, the wheel rim is hard to move, thereby making it somewhat difficult to center the wheel rim.
Further, since an outer cylinder member is adapted to be movable upward and downward, an entire construction of the apparatus becomes complicated and the apparatus is expensive to manufacture. It is necessary to replace the mounting table and the outer cylinder member of the apparatus if the rim diameter of the tire varies. However, it is difficult to replace the mounting table and the outer cylinder member and significant time is required for replacement thereof.
With this arrangement of the prior art, pressurized air to be supplied into the tire when the bead portion of the tire and the bead seat of the wheel are brought into close contact with each other is provided to be supplied only through a clearance formed between the wheel and the bead portion with the annular outer cylinder member for filling inner pressure having an inclined portion at a distal end thereof being pressed against the bead portion of the tire. Thus, there exists a drawback in that the bead portion on the side where the outer cylinder member is pressed against the tire is not uniformly brought into close contact with the bead seat of the wheel.
As described above, these prior art devices both have respective problems to be solved.